1. Field of the Invention
This invention relates to the field of infrared sensors, more particularly to the control of the fan in a Fan Filter Unit for a Standard Mechanical Inter Face.
2. Description of the Prior Art
In prior art the Standard Mechanical Inter Face (SMIF) for control of particulates in semiconductor wafer fabrication uses software control between host, SMIF, and semiconductor wafer equipment to control the operation of the fan in the Fan Filter Unit (FFU). Some of the problems associated with the software control include lengthy integration of host, SMIF, and semiconductor wafer equipment, system down time because of software complexity, and difficulty in trouble shooting.
An arrangement sensing whether a door is open or closed is found in U.S. Pat. No. 4,812,810. In this patent a fiber optic sensor is used to detect if a door or doors of a domestic appliance such as a refrigerator are ajar. U.S. Pat. No. 4,967,083 describes a sensor system for an automatic sliding door employing multiple sensor modules. U.S. Pat. No. 5,329,949 describes activation of a radio remote-controlled vehicle wash system by an infrared motion sensor.